Learn about the fungal battery, made with fungi and fed with organic matter.

Researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa) call this innovative energy-storage system a 'living fungal battery,' as it is based on fungi, " a fascinating kingdom of life, more closely related to animals than to plants, and encompassing a huge variety ," they explain.

The fungal kingdom encompasses all kinds of life forms: from edible creatures to molds; from single-celled creatures to some of the largest organisms on Earth; from disease-causing pathogens to drug-producing superheroes, according to Empa .

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Researchers at this Swiss center have discovered another ability in fungi: the ability to generate electricity. They are harnessing this ability to develop a new type of battery. In addition to being "fungal and living," it is biodegradable (decomposing promptly under the influence of biological agents and environmental conditions) and is printed using 3D technology, simplifying and speeding up its manufacture.

The biggest advantage of the functional fungal battery, developed by Empa's Cellulose and Wood Materials Laboratory, is that, unlike conventional batteries, it is not only completely non-toxic but also biodegradable, according to the researchers.

LIVING CELLS GENERATE ELECTRICITY

They explain that “ the living cells in this battery don’t produce much electricity, but they do produce enough to power a temperature sensor, such as those used in agriculture or environmental research, for several days .”

This battery is based on a technology called "microbial fuel cell," which harnesses the ability of living things (microorganisms, in this case) to convert nutrients into energy, capturing some of that energy in the form of electricity.

Until now, these types of cells have been fueled primarily by bacteria, but Empa researchers have “ combined, for the first time, two types of fungi to create a functional fuel cell ,” according to Carolina Reyes, a researcher at this Swiss laboratory.

TWO TYPES OF FUNGUS ON THE ELECTRODES

The metabolisms (set of cellular chemical reactions) of the two species of fungi complement each other, he points out.

The anode (positive electrode) of the battery contains a yeast whose metabolism releases electrons, while its cathode (negative electrode) is colonized by a white rot fungus, which produces a special enzyme that captures electrons (particles with a negative electrical charge) and conducts them out of the cell.

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Reyes explains that “ the mushrooms are not 'planted' in the battery, but are an integral part of the cell from the beginning .”

The components of the fungal battery are manufactured using 3D printing, allowing researchers to structure the electrodes so that microorganisms can access nutrients as easily as possible by mixing the fungal cells with the printing material.

“ It has been very difficult to find a material that fungi grow well on and that can also easily pass through the 3D printer nozzle without destroying the fungal cells, and that is also electrically conductive and biodegradable ,” says Gustav Nyström, head of Empa’s Cellulose and Wood Materials Laboratory.

Thanks to their lab's extensive experience in 3D printing soft, bio-based materials, the researchers were able to produce a suitable material based on cellulose, a fundamental substance in plant cells and fiber.

“ Fungal cells can even use cellulose as a nutrient, thus contributing to the breakdown of the battery after use, but their preferred source of nutrients is simple sugars, which are added to the battery cells ,” Nyström explains.

“ Fungal batteries can be stored dry and activated in situ simply by adding water and nutrients ,” Reyes adds.

Although the robust fungi survive these dry phases, working with living materials posed several challenges for the researchers, who now plan to increase the power and lifespan of the fungal battery, as well as search for other types of fungi suitable for providing electricity.

“ Fungi are still under-researched and under-utilized, especially in the field of materials science ,” Reyes and Nyström agree.

HIGHLIGHTS :

- Empa Labs' battery is 3D-printed and has four key features that differentiate it from previous technologies: it's made of living matter, requires nutrients, degrades naturally, and is non-toxic.

- The living cells of the fungal battery produce enough electricity to power temperature sensors used in agriculture or environmental research for several days, Swiss specialists explain.

The fungal battery produces small amounts of electricity from two types of fungi; it feeds on both cellulose and simple sugars; and can be stored dry and activated by adding water and nutrients, according to Empa.

By Ricardo Segura EFE-Reports.

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